Once again I got some great help on my Ringo's Good Friend comic from the users of Lang-8. tomochanさん, suteさん, and meguさん all gave corrections here.
Luckily for you, unlike previous comic entries, the grammar was a-OK. However, I received some corrections for word choice and fluency. Such as...
From tomochanさん: まさみ君がその手紙を読んだかどうか気になって、ろくに寝られなかったよ。(The original sentence was まさみ君がその手紙を読んだかどうかって、ろくに寝られなかったよ。)
I think adding 気になって (to worry) helps make the sentence more complete and concise. Perhaps it's comparable to saying "He said he couldn't believe she did that" instead of "He was like I can't believe you did that".
From suteさん: まさみ君がその手紙を読んだかどうかって、ろくに寝られなかった(わ)よ。
わ isn't necessary, but it's a particle often used by women at the end of their sentences, kind of like a softener of sentences, so a sentence including it can seem more natural. I actually asked some people on Lang-8 about it a while ago, since I had heard it being used by men also. (This confused me, since we were told it was strictly a feminine part of speech.) The journal entry is here:
From meguさん: きっと あのまきこって子にはかなわないよね. (The original was でもまきこってあの子にかなわないね.)
I think this is a case of how different cultures prefer words to be grouped (in regards to the あのまきこって子 correction). This correction shows how a Japanese speaker would organize the word structure to have better clarity and more natural sound. I get the feeling it isn't quite equivalent, but compare "that Makiko girl" or "that girl Makiko". I'm sure people have a preference as to which they say or write.